Hi Folks - it's been a while since I last posted, but here's something from today's foray into main dealer land...

Have just changed my alloys for some with M&S tyres on and the speedo is even more out than usual (now around 77-78mph on clock for 70mph on satnav - previously would be about 76 on clock). I remembered (much) earlier threads here saying it was an easy thing to sort out.

I asked the Main dealers here in Durham if it would be a quick job to pop the car on Tech2 to enter the new wheel+tyre size and they said "We're not sure, maybe needs 2 hours and £60 to go through the computer to find out if it's possible"...

When I'd got up off the floor, I thought I'd ask here to confirm - are they having a laugh, or is it really that difficult to find the bit where the wheel+tyre size is entered? IIRC it's either a case of sticking in the numbers on the side of the tyre, or if that doesn't bring it nearer accurate then it's a tape job to measure rolling radius or circumference... Are BS Motors just wanting me to pay for their techs to go and explore?


2006 1.9CDTi(150) Exclusiv
FVMDSH (so it should be up to date on software etc)
No remap

  • Original tyres were 215/50r17 GY NCT5, as usual, on VXL 7x2 spoke Plus Pack alloys

  • Switched to running 225/45r17 94Y size 'summers' - variously GY F1A, current set Falken FK452, which are like driving on oiled glass if it's icy (one Scooby-driving fan of the brand said they "weren't very good" in snow, for which read "bleepin' useless" - a lot worse than the Accelera Alphas I ran on the front for a year, and that's saying something).

  • 'Winter' set - MSW 19 16x7.0j 5-spoke with 205/55r16 91H Conti WinterContact TS830, and very nice they are too, but they are not XL so have more 'squash' which is much better for grip on knobbly stuff, but also means smaller rolling radius from wheel centre to floor.